From Fall 2000 to the present, a fourth digit was added to the course numbers. The 1000-4999 range indicates undergraduate level; the 5000-9999 range indicates graduate level.

CIIS offers workshops to the public on themes related to the Institute's mission. In Fall 1993 CIIS began offering a subset of these workshops for academic credit to its matriculated students. From Fall 1993 to Summer 2000 these workshops were assigned course numbers within the 001-999 range and from Fall 2000 to the present in the 0001-9999 range. All of these workshops bestow graduate-level credit.